We investigated the role of primate dorsolateral prefrontal cortex (dlPFC) neurons in target selection and sustained attention by recording single-cell activity within the area in behaving macaque monkeys. The animals were presented with two colored moving random dot patterns (RDPs), the target and the distracter. The target was defined using a color rank selection rule: turquoise > red > blue > green > pink > grey. All colors were approximately isoluminant and randomly assigned to the stimuli. The animals were required to select the target, sustain attention to it, and detect a transient change in its motion direction. We recorded the activity of 222 neurons, of which 147 (66%) showed an increase in activity during task trials relative to baseline. Out of the 147, 68% reliably encoded the position of the target. This latter group was subdivided into three distinct populations: one group encoded target position transiently, starting ∼150ms after color cue onset (21%, ‘selection neurons’), a second group signaled target position in a sustained manner, starting ∼350 ms after cue onset (42%, sustained attention neurons), and the third group combined features of the aforementioned groups (37%). Using ROC (receiver operating characteristic) analysis we found that these neurons effectively discriminated target and distractor through their firing rate as early as ∼150 ms after cue onset. Moreover, immediately following color cue onset, discrimination occurs earlier for greater distance between target and distractor position in the color-rank scale. This finding follows the animals' behavioral performance; proportion of correct discriminations was higher the greater the distance between target and distractor in the color scale. Overall, our results indicate that different populations of dlPFC neurons may be involved in target selection and sustained attention and that the neurometric performance of these units closely follows the one of the animals.